System and method for distance-dependent data exchange between wireless communication devices

ABSTRACT

In one embodiment, a method includes identifying a plurality of data types; identifying a plurality of communication ranges for data transmission, wherein a first communication range of the plurality of communication ranges is less than a second communication range of the plurality of communication ranges, and wherein the first communication range corresponds to a first data type of the plurality of data types and the second communication range corresponds to a second data type of the plurality of data types; transmitting data in the first data type to a first wireless communication device located within the first communication range; and transmitting data in the second data type to a second wireless communication device located within the second communication range.

PRIORITY

This application claims the benefit, under 35 U.S.C. §119(e), of U.S.Provisional Patent Application No. 61/585,691, filed on 12 Jan. 2012,which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to transmitting data between wirelessdevices.

BACKGROUND

Conventional radios utilize radio metrics to adjust the rate of transferof information from one source to another. The radio metrics may be, forexample, BER (Bit Error Rate) and RSSI (Received Signal StrengthIndication). The metrics are typically found in WLAN (Wireless LocalArea Network) and WAN (Wide Area Network) networks such as 3G, LTE (LongTerm Evolution), CDMA (Code Division Multiple Access), and WiFi systems.In these systems, the rate at which a wireless device can exchange datawith another wireless device is proportional to the distance between thewireless devices. For example, the shorter the distance between thewireless devices, the faster the transmission of data between thewireless devices. Thus, the rate of data transmission changes relativeto the distance between the wireless devices exchanging data. The dataremains the same regardless of the distance between the wirelessdevices, and thus the time it takes to transfer the data increases asthe distance between the devices increases.

SUMMARY OF PARTICULAR EMBODIMENTS

According to one aspect, systems and methods are provided for providingdata that is adjusted according to the distance between wireless devicesexchanging the data. In one embodiment, spatial zones of information arecreated as a function of the distance between wireless devices. In oneexample, data to be transmitted from a first wireless device to a secondwireless device is adjusted based on which spatial zone of informationthe second wireless device is located in.

In some embodiments, a first wireless device may transmit data that canonly be received by one or more second wireless devices within aspecific distance from the first wireless device. Those wireless devicesbeyond the specific distance from the first wireless device are not ableto receive the data. There may be different types of data associatedwith different distances.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example wireless communications system.

FIG. 2 illustrates an example wireless communications system includingwireless devices positioned at different distances.

FIG. 3 illustrates an example wireless communications system forwirelessly transmitting data between wireless devices.

FIG. 4 illustrates an example data encoding matrix.

FIG. 5A illustrates an example orthogonal frequency division multipleaccess (OFDM) transmitter.

FIG. 5B illustrates an example OFDM receiver.

FIG. 5C illustrates an example simple superheterodyne transmitter.

FIG. 5D illustrates an example simple superheterodyne receiver.

FIG. 6 illustrates transmit power at various distances.

FIG. 7 illustrates an example user interface for controllingtransmission ranges.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 is a diagram of a communications system 100. The communicationsystem 100 includes wireless communication devices 104 a, 104 b, 104 cand 104 d. The first wireless communication device 104 b is a firstdistance 110 from the primary wireless communication device 104 a. Thesecond wireless communication device 104 c is a second distance 111 fromthe primary wireless communication device 104 a. The third wirelesscommunication device 104 d is a third distance 112 from the primarywireless communication device 104 a. In a conventional wirelesscommunications system, the wireless communication devices 104 b, 104 cand 104 d are within a range of communication 124 a of the primarywireless communication device 104 a, and if data sharing is enabled onthe primary wireless communication device 104 a, then all wirelesscommunication devices 104 b-104 d within the range of communication 124a have access to the same data.

The range of communication 124 a may depend on the wireless technologyfor data transmission used by the primary wireless communication device104 a. Examples of wireless communications technologies include NearField Communications (NFC), Bluetooth, WiFi, and a cellular network suchas GSM, 3G, 4G or LTE. If a wireless communication device 104 b-104 d isinside the communication range 124 a of the primary wirelesscommunication device 104 a, then the wireless communication devices 104b-104 d can exchange data with the primary communication device 104 a.The first distance 110 between the primary communication device 104 aand the first communication device 104 b is the shortest, and in someembodiments, this would allow communication between the wirelesscommunication devices 104 a and 104 b at the highest availablethroughput. The second distance 111 is greater than the first distance110, and thus the second wireless communication device 104 c may have alower available throughput. However, since the second wirelesscommunication device 104 c is within the communication range 124 a, thesecond wireless communication device 104 c maintains access to the samedata as the first wireless communication device 104 b. Furthermore, thethird distance 112 is greater than the second distance 111, so the thirdwireless communication device 104 d may have the lowest availablethroughput. However, since the third wireless communication device 104 dalso remains within the communication range 124 a, the third wirelesscommunication device 104 d maintains access to the same data as thefirst 104 b and second 104 c wireless communication devices. In oneexample, these embodiments would be typical of a WiFi system in whichthe communication ranges 124 a, 124 b, 124 c, and 124 d have a radius ofabout one hundred meters and the distances 110, 111, and 112 are lessthan about 100 meters in an indoor and/or multipath environment.

According to various embodiments, the wireless communication devices 104a-104 d may include one more mobile phones, iPhones, headphones,headsets (including a microphone and earphone), music players, iPods,personal digital assistants, iPads, laptops, computers, tabletcomputers, or cameras.

FIG. 2 is a diagram of a communications system 200. The wirelesscommunication devices 104 b, 104 c, and 104 d are at different distances210, 211 and 212 from the user 104 a. As shown in FIG. 2, the thirdwireless communication device 104 d is unable to communicate with theprimary communication device 104 a since the distance 212 between thecommunication devices 104 a and 104 d is too large and the primarycommunication range 124 a does not overlap with the third communicationrange 124 d. The wireless communication devices 104 b and 104 c arewithin the communication range 124 a, and are able to communicate withthe communication device 104 a, as described above with respect toFIG. 1. In this embodiment, the third wireless communication device 104d is not able to access information from the primary wirelesscommunication device 104 a due to a distance-dependent threshold incommunication.

FIG. 3 is a diagram of a communications system 300 according to oneembodiment. According to one aspect, the communication device 304 asimultaneously transmits multiple data streams each having differenttypes of coded data. The communication device 304 a has three levels ofcommunication ranges, 330, 331, 332. The communication range 330includes transmitted data included in the first data type 320. Thecommunication range 331 includes transmitted data included in the seconddata type 321. The communication range 332 includes transmitted dataincluded in the third data type 322. The type of data that may betransmitted from the primary communication device 304 a depends on thedistance between the primary communication device 304 a and the deviceto which it is attempting to transmit data. For example, data includedin the first data type 320 may be transmitted to devices within thefirst communication range 330, data included in the second data type 321may be transmitted to devices within the second communication range 331,and data included in the third data type 322 may be transmitted todevices within the third communication range 332.

In some embodiments, the data types 320, 321 and 322 may be transmittedsimultaneously on different radios operating at differentelectromagnetic wavelengths, different antennas, and/or differentmodulation, demodulation and encoding formats. Different modulation,demodulation and encoding formats may be used to minimize the hardwarecomplexity of the primary wireless communication device 304 a. In oneexample, the first wireless communication device 304 b at communicationdistance 310 has access to the first data type 320, the second data type321 and the third data type 322. The second wireless communicationdevice 304 c at communication distance 311 has access to the second datatype 321 and the third data type 322. The third wireless communicationdevice 304 d at communication distance 312 has access to the third datatype 322. The user of the primary wireless communication device 304 amay control the type of information provided at each data type level320, 321 and 322. In one example, the user interface of the wirelesscommunication device 304 a may be designed to allow the user to controlthe type of information available at each data type level 320, 321 and322.

In FIG. 3, the communication range 330 is shorter than the communicationrange 331, which in turn is shorter than the communication range 332. Insome embodiments, when the first data type 320 is transmitted from thecommunication device 304 a, only the communication device 304 b canreceive it because only the communication device 304 b is within thecommunication range 330. However, when the second data type 321 istransmitted from the communication device 304 a, both of thecommunication devices 304 b and 304 c can receive it because both of thecommunication devices 304 b and 304 c are within the communication range331. Similarly, when the third data type 322 is transmitted from thecommunication device 304 a, all three of the communication devices 304b, 304 c, and 304 d can receive it because all three of thecommunication devices 304 b, 304 c, and 304 d are within thecommunication range 332.

In some embodiments, the information provided in the first data type 320may be more private or secure than information provided in the seconddata type 321, and the information provided in the second data type 321may be more private or secure than information provided in the thirddata type 322. In accordance with one embodiment of the invention, theradius 310 of the first communication range 330 may be less than aboutone meter and the first data type 320 may be very personal informationsuch as contact information, private documents and files, or URLs topersonal or public information on the internet. The data included in thefirst data type 320 may be information that the user of the primarycommunication device 304 a intentionally shares specifically with theuser of the first communication device 304 b. To further improvesecurity, users of the wireless communication devices 304 a and 304 benable exchange of information in the first data type 320 only afterfirst sharing other information such as device orientation, inertialsignatures, passwords, PINS (personal identification numbers), NFC, orRFID data exchange. In one example, the first wireless communicationdevice 304 b may be another wireless device owned by the user of theprimary communication device 304 a such as a watch, pedometer, heartrate monitor, fitness equipment or headphones, or any combination ofthese.

In one embodiment, the radius 311 of the second communication range 331may be less than three meters and the second data type 321 may bepersonal information that the user of the primary communication device304 a intends to share with a group of people. For example, theinformation in the second data type 321 may be contact information,documents, and/or files or URLs to personal or public information on theinternet. The information in the second data type 321 may be informationthat is often inefficiently shared at business meetings and socialgatherings.

The radius 312 of the third communication range 332 may be greater thanten meters and the third data type 322 may be public information thatthe user of the primary communication device 304 a intends to sharebroadly in a large public setting. For example, the information includedin the third data type 322 may be information the user of the primarycommunication device 304 a intends to share with other communicationdevices in a classroom, lecture hall, airplane, restaurant or bar, urbanoutdoor environment, and/or mall. In another example, the information inthe third data type 322 may be information the user of the primarycommunication device 304 a would like to share with any device withinthe selected range, such as any device within ten meters of the primarycommunication device 304 a while the user ambulates outside.

FIG. 4 is a diagram of an embodiment of a data encoding matrix 400 thatmay be used to create the three different data types 320, 321 and 322shown in FIG. 3. FIG. 4 shows a matrix of the three data types 320, 321and 322 in bits that may be fed into a transmitter, such as anOrthogonal Frequency Division Multiplexing (OFDM) transmitter. The firstdata type 320 is represented in first column 401, the second data type321 is represented in a second set of columns 406, and the third datatype 322 is represented in a third set of columns 411.

Referring to FIG. 4, the first data type 320 is shown as a first column401 vector of N bits. The second data type 321 is shown as L redundantcopies 405 of one column vector of the second set of columns 406. Thethird data type 322 is shown as M redundant copies 410 of one columnvector of the third set of columns 411. According to one example, if theentries in the second set of columns 406 are all identical, thebandwidth of the second data type 321 can be reduced to N×L times lowerthan the bandwidth of the first data type 320. According to one feature,as shown in FIG. 3, the third data type 322 is broadcast at a longerrange than the second data type 321, and, referring to FIG. 4, thenumber of redundant copies 410 (M) of the third data type 322 is largerthan the number of redundant copies 405 (L) of the second data type 321.

According to one embodiment, a data stream from a wireless communicationdevice is a continuous stream of matrices 400. In the matrix 400, krepresents the time index. A transceiver in the wireless communicationdevice includes an encoding module that may use an OFDM encoding method.The OFDM encoding method converts a parallel bit stream to a set oforthogonal signals. The transceiver simultaneously transmits the set oforthogonal signals. In one example, the transceiver includes a linearanalog transmitter that performs the simultaneous transmission of theset of orthogonal signals. According to one embodiment, the set oforthogonal signals is created using non-overlapping orminimally-overlapping signals in the frequency domain, resulting inorthogonal frequency data. A Fast Fourier Transform (FFT) may be used toconvert the superposition of orthogonal frequency data into thetime-domain.

In one embodiment, distance-dependent data is generated by adjusting thebandwidth of a bit of data for each data type. For example, the shortestdistance data type, the first data type 320, uses a high bandwidth,while the longest distance data type, the third data type 322, uses alow bandwidth. In one embodiment, the bandwidth may be reduced by makingredundant copies of the same bit and designing the receiver to integrateor average the signals. The low bandwidth signal used for the third datatype 322 allows the data to be received at a distance further from thetransmitter. The signals may be averaged in the time domain or thesignals may be averaged in the frequency domain. In one example, thereceiver has information about which receiver signals to average. Theinformation about which signals to average may have been previouslyshared with the wireless communication device to which the transceiverwill transmit the data or from which it is receiving a signal. Inanother embodiment, distance-dependent data is generated by adjustingthe transmit power for each data type.

In one embodiment, the data in the matrix 400 may be more interleavedthan is shown in FIG. 4. In other embodiments, the data in the matrix400 may be represented in different encodings or modulation formats tominimize latency or optimize some other system parameter. In a furtherembodiment, the value of L (the number of copies 405) and the value of M(the number of copies 410) may be fixed a priori information sharedacross the wireless communications devices 304 a, 304 b, 304 c and 304d. In another embodiment, the value of L (the number of copies 405) andthe value of M (the number of copies 410) may be broadcast as third datatype 322 information or by means of another wireless protocol with alonger range.

FIG. 5A is a diagram of an OFDM transmitter 500 according to anembodiment, and FIG. 5B is a diagram of an OFDM receiver 524 accordingto an embodiment. According to one aspect, an OFDM transceiver includesthe OFDM transmitter of FIG. 5A and the OFDM receiver of FIG. 5B.

Referring to FIG. 5A, an incoming data stream x[n] 501 may be, forexample, a serialized version of the matrix shown in FIG. 4. Theincoming data stream x[n] 501 is converted into multiple parallel datastreams 502, and a constellation mapping 508 is used to map the paralleldata streams 502 to a constellation of orthogonal signals 503, 504, 505,and 506. In one example, the orthogonal signals 503-506 may be modulatedusing QAM (Quadrature Amplitude Modulation) or PSK (Phase Shift Keying).

The orthogonal signals 503-506 are converted to time domain signalsusing an inverse Fast Fourier Transform 509 (FFT). The FFT 509 producesa complex time-series signal including a real signal component 510 andan imaginary signal component 511. The real signal component 510 isinput converted to an analog signal at a first digital-to-analogconverter 512, and the imaginary signal component 511 is converted to ananalog signal at a second digital-to-analog converter 513. The realsignal component 510 is then converted to the radiofrequency (RF) domainvia a first mixer 515 and the imaginary signal component 511 isconverted to the radiofrequency domain via a second mixer 516. Themixers 515 and 516 receive a local oscillator signal from the localoscillator 514, and multiply the local oscillator signal by therespective real and imaginary complex time series signals. In oneexample, the local oscillator signal is in the range of about 2.45 GHz,and the output from the transmitter is WiFi or another microwavefrequency. The real 510 and imaginary 511 components are combined at 518to produce the output signal x(t) 519. The output signal x(t) 519 isamplified by amplifier 520 and radiated by an antenna 521 as microwaveelectromagnetic fields. In one example, the matrix 400 in FIG. 4 may befed into the transmitter 500 column-by-column to transmit the variousdata types.

Referring to FIG. 5B, the receiver 524 includes an antenna 525 thatconverts electromagnetic fields to a voltage signal y(t) 526. Thevoltage signal y(t) may be an attenuated and distorted version of anoutput signal from another wireless communication device, similar to theoutput signal x(t) 519 of the transmitter. The attenuation anddistortion of the output signal as received at the receiver 524 may becaused by path loss and/or scattering in the environment. The receivedvoltage signal y(t) is divided into two parallel input signals and inputinto mixers 527 and 529. The mixers 527 and 529 convert the parallelinput signals to baseband using a local oscillator 534. Baseband filters530 and 535 filter out the double frequency component of each parallelinput signal. The output from the baseband filters 530 and 535 isamplified at amplifiers 531 and 536, and then the complex analogtime-series input signals are converted to the digital domain withanalog-to-digital converters 532 and 537.

The complex digital time-series input signals are processed by the FFT539. In one embodiment, the FFT 539 averages the samples in the complexdigital time-series input signals according to a shared a prioriknowledge of the indices L and M, as discussed above with respect toFIG. 4. In one example, the FFT 539 includes sufficient memory to storereceived samples for averaging. According to one example, the matricesare framed. The FFT 539 outputs orthogonal signals that are converted tosymbols by the symbol detection block 545. In another embodiment, thesymbol detection block 545 averages the samples in the complex digitaltime-series input signals according to a shared a priori knowledge ofthe indices L and M, as discussed above with respect to FIG. 4. Thesymbol detection block 545 may include sufficient memory to storereceived samples for averaging. According to one feature, the averagingperformed by the FFT 539 or the symbol detection block 545 results in aprocessing gain, allowing for the use of a smaller bandwidth for alonger range. After appropriate averaging, the symbol detection block545 detects the symbols and converts the signals to bits. The multipleparallel orthogonal signals 540-543 are converted from parallel to aserial stream of bits y[n] 551.

In some instances, radios may have transceiver architectures that aresimpler than OFDM. Examples include RFID at UHF and microwavefrequencies, Bluetooth Low Energy 4.0, Bluetooth 1.0, 1.1, 1.2, 2.0, 2.1(Classic Bluetooth), the earlier WiFi protocols (802.11b and g) andproprietary 433, 900 MHz and 2.4 GHz radios. In these instances, thesize of the orthogonal basis set may be smaller, and therefore theencoding for distance-dependent communications may be different. Forexample, if the modulation is done with ASK, FSK (including GFSK, DQPSKand DPSK), the distance-dependent coding may be done with repetitioncodes, dynamically changing rate codes, or other codes. FIGS. 5C and 5Dillustrate a conventional radio architecture which may be used foractive radio systems that are not based on RFID (the complexity of theRFID antenna arrangement for transmit 566 and receive 575 are different,but not shown in these figures for sake of simplicity). For thetransmitter 550, digital samples representing baseband modulation in thereal 551 and imaginary domain 553 are fed into DACs 552 554 which arethen modulated with a local oscillator 555, mixers 556 558, and a phaseshifter 557 and then combined 559 to produce a complex RF signal 560.This signal can then be amplified 565 and radiated 566. The basebandsamples 551 553 may correspond to samples that compose repetition ormodulation rates codes for each distance-dependent communication range.Upon reception of a radiated signal at the antenna 575, a complex RFsignal 576 is demodulated and filtered by components 577 578 579 580 584585. The analog signal is amplified 581 586 and then digitized 582 587.If a repetition code or similar coding scheme is utilized, a dynamicaveraging block 589 may be used to assemble larger symbols fromindividual samples or chips. If a different modulation rate is used, thedynamic averaging block 589 may choose larger symbols to apply anappropriately-sized matched filter or other filter. Finally, a symboldetection block 595 extracts bits from the sequence, which may then beconverted into a bit stream in memory.

FIG. 6 is a diagram showing the transmit power at various distances fora matrix such as that shown in FIG. 4 with N×L=16 and N×M=256. Thecombined transmit power and antenna gain of the originating wirelesscommunication device's transmitter is set to −40 dBm, allowing forcommunication of the first data type 601 at a first distance d1 605(0.73 m), communication of the second data type 602 at a second distanced2 606 (2.9 m), and communication of the third data type 603 at a thirddistance d3 607 (11.7 m) with a 300 Mbit/s OFDM transceiver.Communication of different data types at different distances may beenabled digitally if, for example, the transmitter has sufficientdynamic range. In another example, communication of different data typesat different distances may be enabled digitally with an analogattenuator in the transmit chain. According to one feature, the lowpower level may be selected to ensure privacy. For example, if users ofother wireless communication devices do not change the temperature oftheir receivers or employ enormously large, conspicuous antennas, it isthermodynamically not possible to decode data beyond a certain range.This is because, according to equation (1) below, there is a minimumsignal to noise ratio beyond which no information can be reliablyobtained:SNR_(min) _(—) _(in) _(—) _(dB)=10 log₁₀ k _(B) T+10 log₁₀ BW+Eb/N_(0BER) +NF+IL _(modulation).  (1)

The first term represents the noise floor in the channel based on thethermodynamics of operating a receiver at a particular temperature. Thesecond term represents how much of the channel is utilized as bandwidthfor integrating the noise power. The third term is the theoreticalsignal to noise ratio in dB for a specific bit error rate (BER) andmodulation format. The theoretical signal to noise ratio for a specificBER and modulation format is −1.6 dB at the Channel capacity limit, butis otherwise a positive number. The fourth term represents animplementation loss in the analog domain of a circuit corresponding tothe noise temperature of the receiver and is typically in the range ofabout 0.5-20 dB. The last term is a digital implementation losscorresponding to, for example, finite dynamic range, computationalpower, distortion/interference and timing errors. The digitalimplementation loss varies from about 0.5-10 dB in typical systems.Given that NF and IL are positive numbers, the variables under areceiving user's control are temperature and the receiving user'sreceiving antenna gain. Otherwise, the minimum power required toproperly decode information from a transmitter may be used as a means ofguaranteeing physical access to the various data types.

According to one feature, the −77 dBm limit for the first data type 601is the minimum receiver power of typical 802.11n radios on the marketthat transmit at 300 mbit/s. The other data type power levels and rangesare determined from this data point using the Friis transmissionequation, represented by the curve 610. According to one embodiment, theranges discussed with respect to Equation (1) may change slightly due toscattering. In another embodiment, the transmitter power may be higher,but the protocol ensures that the receiver power threshold is set abovethe corresponding limit.

In some embodiments, different types of data are transmitted atdifferent power levels so that the signals can only reach specific anddifferent distances (e.g., due to ambient temperature or noise ratio).For example, in FIG. 3, the first data type 320 may be transmitted at alower power level so that the signals only reach a short distance (e.g.,the communication range 330). The second data type 321 may betransmitted at a somewhat higher power level so that the signals canreach a somewhat longer distance (e.g., the communication range 331).The third data type 322 may be transmitted at an even higher power levelso that the signals can reach a farther distance (e.g., thecommunication range 332). These power levels may be dynamicallycontrolled by a power amplifier, or using the dynamic range of thedigital to analog converters.

FIG. 7 is a diagram of a user interface element that may be used tocontrol the communication ranges for the different data types on amobile communication device. The user can control the zones ofcommunication 725 corresponding to the first data type and the seconddata type. According to one embodiment, the third data type may bebroadcast using the same radio, and the third data type may also bebroadcast widely using WAN technology connected to the internet such asa cellular modem or WiFi. Thus, the communication range of the thirddata type may be considered as infinite or global. As shown in FIG. 7,the range of the first data type, shown here as Virtual contact info 731has a control distance 736 that can be dynamically changed using a touchscreen or other user interface control. The radius of communication mayupdate live on the screen as a user changes this parameter. The user mayalso add or subtract the types of information that may be shared withinthe first distance 731. Similarly, the second data type, shown in FIG. 7as Group of friends 730, has a control distance 735 that can bedynamically changed. In one embodiment, a set of profiles for varioussocial settings may be defined by a user and the user may switch betweenthe settings, or the communication device may automatically switchsetting based on location-awareness.

Having thus described several aspects of at least one embodiment, it isto be appreciated various alterations, modifications, and improvementswill readily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to be part of thisdisclosure and are intended to be within the scope of the invention.Accordingly, the foregoing description and drawings are by way ofexample only, and the scope of the invention should be determined fromproper construction of the appended claims, and their equivalents.

What is claimed is:
 1. A method comprising: by a primary communicationdevice, identifying a plurality of data types; by the primarycommunication device, identifying a plurality of communication rangesfor data transmission, wherein a first communication range of theplurality of communication ranges is less than a second communicationrange of the plurality of communication ranges, and wherein the firstcommunication range corresponds to a first data type of the plurality ofdata types and the second communication range corresponds to a seconddata type of the plurality of data types; by the primary communicationdevice, transmitting data in the first data type to a first wirelesscommunication device located within the first communication range,wherein the data in the first data type is transmitted using a firstbandwidth based on the first communication range; and by the primarycommunication device, transmitting data in the second data type to asecond wireless communication device located within the secondcommunication range, wherein the data in the second data type istransmitted using a second bandwidth based on the second communicationrange, the second bandwidth being lower than the first bandwidth, andwherein the data in the first data type is undecodable by the secondwireless communication device at the second communication range.
 2. Themethod of claim 1, wherein: the data in the first data type and the datain the second data type are transmitted simultaneously; the data in thefirst data type are transmitted at a first power level; and the data inthe second data type are transmitted at a second power level greaterthan the first power level.
 3. The method of claim 2, furthercomprising: by the primary communication device, receiving firstfeedback information from the first wireless communication device; bythe primary communication device, receiving second feedback informationfrom the second wireless communication device; by the primarycommunication device, adjusting the first power level based on the firstfeedback information; and by the primary communication device, adjustingthe second power level based on the second feedback information.
 4. Themethod of claim 1, further comprising: by the primary communicationdevice, encoding the data in the first data type using a first encodingformat; and by the primary communication device, encoding the data inthe second data type using a second encoding format.
 5. The method ofclaim 4, wherein the data in the first data type and the data in thesecond data type are encoded by an Orthogonal Frequency DivisionMultiplexing (OFDM) encoder configured to convert a bit stream of datato a set of orthogonal signals.
 6. The method of claim 5, furthercomprising transmitting the set of orthogonal signals simultaneously. 7.The method of claim 1, wherein: the data in the first data type is onlydecodable by the first wireless communication device; and the data inthe second data type is only decodable by the first and second wirelesscommunication devices.
 8. The method of claim 1, further comprising: bythe primary communication device, transmitting data in a third datatype, wherein the data in the third data type is only decodable by thefirst and second wireless communication devices and a third wirelesscommunication device located within a third communication range, whereinthe third communication range is greater than the second communicationrange.
 9. The method of claim 8, wherein: the data in the first, second,and third data types are transmitted simultaneously by the primarycommunication device; the data in the first data type is undecodable bythe third wireless communication device; and the data in the second datatype is undecodable by the third wireless communication device.
 10. Themethod of claim 8, wherein the data in the third data type istransmitted using a third bandwidth, the third bandwidth being lowerthan the second bandwidth.
 11. A wireless communications devicecomprising: a transmitter configured to: transmit data in a first datatype to a first wireless communication device located within a firstcommunication range, wherein the data in the first data type istransmitted using a first bandwidth based on the first communicationrange; and transmit data in a second data type to a second wirelesscommunication device located within a second communication range,wherein the data in the second data type is transmitted using a secondbandwidth based on the second communication range, the second bandwidthbeing lower than the first bandwidth, and wherein the data in the firstdata type is undecodable by the second wireless communication device atthe second communication range; and a receiver configured to receivedata transmitted from the first communication device and the secondcommunication device.
 12. The wireless communications device of claim11, further comprising an encoder configured to encode the data in thefirst data type and the data in the second data type.
 13. The wirelesscommunications device of claim 12, wherein the encoder is an OrthogonalFrequency Division Multiplexing (OFDM) encoder configured to convert abit stream of data to a set of orthogonal signals.
 14. The wirelesscommunications device of claim 13, wherein the transmitter is furtherconfigured to transmit the set of orthogonal signals simultaneously. 15.The wireless communications device of claim 11, wherein: the data in thefirst data type and the data in the second data type are transmittedsimultaneously; the data in the first data type are transmitted at afirst power level; and the data in the second data type are transmittedat a second power level greater than the first power level.
 16. Thewireless communications device of claim 15, wherein: the receiver isfurther configured to: receive first feedback information from the firstwireless communication device; and receive second feedback informationfrom the second wireless communication device; and the transmitter isfurther configured to: adjust the first power level based on the firstfeedback information; and adjust the second power level based on thesecond feedback information.
 17. The wireless communications device ofclaim 11, wherein: the data in the first data type is only decodable bythe first wireless communication device; and the data in the second datatype is only decodable by the first and second wireless communicationdevices.
 18. The wireless communications device of claim 11, wherein thetransmitter is further configured to: transmit data in a third datatype, wherein the data in the third data type is only decodable by thefirst and second wireless communication devices and a third wirelesscommunication device located within a third communication range, whereinthe third communication range is greater than the second communicationrange.
 19. The wireless communications device of claim 18, wherein: thedata in the first, second, and third data types are transmittedsimultaneously by the transmitter; the data in the first data type isundecodable by the third wireless communication device; and the data inthe second data type is undecodable by the third wireless communicationdevice.
 20. The wireless communications device of claim 18, wherein thedata in the third data type is transmitted using a third bandwidth, thethird bandwidth being lower than the second bandwidth.
 21. A methodcomprising: sending, by a first wireless device, first data, wherein thefirst data are only decodable by one or more second wireless deviceswithin a first distance from the first wireless device, and the firstdata are sent using a first bandwidth based on the first distance; andsending, by the first wireless device, second data, wherein the seconddata are only decodable by the one or more second wireless devices andone or more third wireless devices within a second distance from thefirst wireless device, the second distance being greater than the firstdistance, and the second data are sent using a second bandwidth based onthe second distance, the second bandwidth being lower than the firstbandwidth.
 22. The method of claim 21, wherein the first data areundecodable by the one or more third wireless devices outside of thefirst distance.
 23. The method of claim 21, wherein: the first data andthe second data are sent simultaneously by the first wireless device;the first data are sent at a first power level; and the second data aresent at a second power level greater than the first power level.
 24. Themethod of claim 23, further comprising: by the first wireless device,receiving first feedback information from one of the second wirelessdevices; by the first wireless device, receiving second feedbackinformation from one of the third wireless devices; by the firstwireless device, adjusting the first power level based on the firstfeedback information; and by the first wireless device, adjusting thesecond power level based on the second feedback information.
 25. Themethod of claim 21, further comprising: encoding, by the first wirelessdevice, the first data using a first encoding format; and encoding, bythe first wireless device, the second data using a second encodingformat.
 26. The method of claim 25, wherein the first data and thesecond data are encoded by an Orthogonal Frequency Division Multiplexing(OFDM) encoder configured to convert a bit stream of data to a set oforthogonal signals.
 27. The method of claim 26, further comprisingtransmitting the set of orthogonal signals simultaneously.
 28. Themethod of claim 21, further comprising: by the first wireless device,associating a first data type with the first distance, wherein any dataof the first data type sent by the first wireless device are onlydecodable by the one or more second wireless devices within the firstdistance from the first wireless device; and by the first wirelessdevice, associating a second data type with the second distance, whereinany data of the second data type sent by the first wireless device areonly decodable by the one or more second wireless devices and the one ormore third wireless devices within the second distance from the firstwireless device.
 29. The method of claim 21, further comprising sending,by the first wireless device, third data, wherein the third data areonly decodable by the one or more second wireless devices, the one ormore third wireless devices, and one or more fourth wireless deviceswithin a third distance from the first wireless device, the thirddistance being greater than the second distance.
 30. The method of claim29, wherein: the first data, the second data, and the third data aresent simultaneously by the first wireless device; the first data areundecodable by the one or more fourth wireless devices outside of thefirst distance; and the second data are undecodable by the one or morefourth wireless devices outside of the second distance.
 31. The methodof claim 29, wherein the third data are sent using a third bandwidthlower than the second bandwidth.